Indeed, Farseer Helper is a great thing. However, it has not provided enough helper documents related to its API. This is, in my opinion, one of the may cause that Farseer Helper( including Farseer itself) has not prevailed to such an extend as far as the
author initially imaged.

Sorry you're having issues with Farseer and the Physics Helper. Please keep in mind that these are volunteer based projects by the community. If you are interested in volunteering time to document or otherwise contribute, please contact myself for Physics
Helper, or for Farseer Physics, one of the Farseer Physics team members.

That said, I think there are some good sources of documentation for starters though:

I'm not sure if you are refering to the "Could not determine the outline" error, which is quite common, or if you are just venting? But this error is usually because of the boundary detection algorithm trying to determine the outline
of an image you are using. This algorithm works by tracing a path around the pixels in the image, but doesn't work if you have any stray pixels sitting around outside the image's shape. You also need to make sure everything is in a Canvas located at x,y =
0,0 in your visual tree (You can change this after the Initialized event raised by the PhysicsController. (Admittedly this is a bit touchy!)

Also, there are several posts on Adding Physics Behaviors Programmatically -